Extract GST amount and calculate the original price from GST-inclusive amount. Get CGST, SGST, and IGST breakdown with reverse calculation formula for 2025.
Extract GST amount and calculate original price from GST-inclusive amount with CGST/SGST/IGST breakdown
What is Reverse GST?
When you have a GST-inclusive price and want to extract the GST amount and find the original price before tax.
Enter the total amount you paid (including GST)
Quick Select (Latest 2025 Rates):
Add multiple items with different GST rates to calculate total breakdown
Reverse GST calculation is the process of extracting the GST component from a GST-inclusive price to find the original base price. This is useful when you know the final price (including GST) and need to determine how much of it is tax and how much is the actual product/service cost.
Original Price =
Inclusive Amount ÷ (1 + GST Rate/100)
GST Amount =
Inclusive Amount - Original Price
Given: Final price = ₹1,180 (including 18% GST)
Original Price:
= 1,180 ÷ (1 + 18/100)
= 1,180 ÷ 1.18 = ₹1,000
GST Amount:
= 1,180 - 1,000 = ₹180
CGST: ₹90 | SGST: ₹90
When buyer and seller are in the same state, GST is split equally into CGST (Central) and SGST (State).
Example: ₹180 GST at 18%
CGST (9%) = ₹90
SGST (9%) = ₹90
When buyer and seller are in different states, entire GST is collected as IGST (Integrated GST).
Example: ₹180 GST at 18%
IGST (18%) = ₹180
(No CGST/SGST split)
Verify if GST charged on invoices is correct by extracting the GST component from the total amount.
Calculate profit margins by determining the base cost when you only know the GST-inclusive selling price.
Maintain accurate books of accounts by separating revenue from GST liability in price-inclusive transactions.
Our Reverse GST Calculator is a powerful tool that helps you extract the GST component from a GST-inclusive amount. Whether you're a business owner, accountant, or consumer, this calculator simplifies the process of determining the original price and tax amount from the final price.
Perfect for calculating reverse GST on a single transaction:
Ideal for invoices with multiple items at different GST rates:
As per the GST 2.0 reforms effective from September 22, 2025, the calculator supports all current GST rates including the new 40% rate for luxury and sin goods (replacing the earlier 28% + cess structure). The primary rates are 5% and 18%, with 0%, 3%, 12%, 28%, and 40% available for specific categories.